Answer:
Step-by-step explanation:
For this case we want to find the density function for 
And we have the following density function for the random variable X:

So we can do this replacing 

If we apply square root on both sides we got:

And if we integrate we got this:
![F_Y (y) = [t+ \frac{t^2}{2}] \Big|_{-\sqrt{y}}^0+ [t -\frac{t^2}{2}] \Big|_{0}^{\sqrt{y}}](https://tex.z-dn.net/?f=%20F_Y%20%28y%29%20%3D%20%5Bt%2B%20%5Cfrac%7Bt%5E2%7D%7B2%7D%5D%20%5CBig%7C_%7B-%5Csqrt%7By%7D%7D%5E0%2B%20%5Bt%20-%5Cfrac%7Bt%5E2%7D%7B2%7D%5D%20%5CBig%7C_%7B0%7D%5E%7B%5Csqrt%7By%7D%7D%20)
And replacing we got:
![F_Y (y) = [0 -(-\sqrt{y} +\frac{y}{2})] + [\sqrt{y} -\frac{y}{2}]](https://tex.z-dn.net/?f=%20F_Y%20%28y%29%20%3D%20%5B0%20-%28-%5Csqrt%7By%7D%20%2B%5Cfrac%7By%7D%7B2%7D%29%5D%20%2B%20%5B%5Csqrt%7By%7D%20-%5Cfrac%7By%7D%7B2%7D%5D)

And if we want to find the density function we just need to derivate the pdf like this:
We know that the smaller base is x cm, the greater base is x+4 cm, and that the height is x/2 cm.
Since the area of a trapezium is given by

If we plug the expressions we have

If this must equal 84, we can solve for x as follows: start with

Multiply both sides by 4:

Subtract 336 from both sides:

We can divide both sides by 2 to make computation simpler:

Use the quadratic formula (or any mean you prefer) to solve this equation and get the solutions

We can't accept the negative solution, because it would imply

and we can't have negative side lengths. So, the answer is 12.
Answer:
Tax=6%
So original price=100%
New price =100%+6%=106%
10.5*(106/100)=
10.5*1.06=11.13
55*1.06= 58.3
58.3-11.13= 47.17
The difference is 47 dollars
$47
Set up an equation to solve for the tax rate, x:

We can conclude that the tax rate on the computer was 6.5 percent.
Answer:
c
Step-by-step explanation:
hope this helps!! :)